How do you identify wild orchids that might you come across while going for a walk or trekking, from other plants? Let this article help you out. Large amount of variation is seen in flowers as well as the leaves/ stem/roots (vegetative structures) of the orchids. However, researchers differ on this, with some stating flowers being more diverse than the vegetative structures, while the other group opines vegetative structure to be more diverse.

To identify orchids from other wild plants you can keep in mind a few general points, which can help in recognising some common orchids. There are the two major groups of orchids, epiphytes and terrestrials. Each has been taken up separately.

Epiphytes: These types of orchids are found growing on trees/poles, sometimes even on overhanging wires! Majority of orchids belong to this group and are mostly found in the tropics. In the wild, these orchids are often confused with other epiphytes such as lianas, ferns etc. I have faced this problem myself, while searching orchids in the tropical rainforests of North-Eastern India. So the general key to identifying epiphytic orchids is:
1. Identifying from the vegetative structures: Many orchids have bulbous structure from which single or at the most two leaves arise. Ferns have rhizomes which give out leaves in large numbers. The rhizomes of the ferns are very different looking from the bulbous structures of orchids. Orchid bulbs are generally shiny or sheathed, while the rhizomes of the ferns are mostly covered with hairy structures and are rough in texture. Some orchids have stem like structures from which leaves arise in a row, these can be confused with the lianas. The difference between these two is that in winter lianas remains green whereas the orchids mostly shed their leaves, the stem shrivels and take on a wrinkled look. Lianas are vines, the stem is flexible unlike the rigid stem of orchids. Bunches of mistletoe (in temperate zones) might look like orchids from a distance, but orchids are not parasitic like the mistletoe.
2. Identifying from the flowers: Ferns do not flower; they have leaf fronds, period. Lianas also have very colourful flowers like orchids. The differently shaped third petal, called the labellum, of the orchid flower differentiates it from almost all other flowers.

Terrestrials: You will find these are orchids growing in soil, on rocks, under the shade of trees or in open sunny grasslands.
1. Identifying terrestrial orchids is somewhat more difficult, unless it is flowering. Otherwise, the vegetative plant (without flower) resembles other plants like bromeliads, philodendrons, etc. Most terrestrial orchids have underground rhizome (stem like structure), which gives out leaves so that the leaves appear to be comes out of the ground. The leaves are mostly sheathed (like in lilies); though, some orchids have alternately arranged leaves too.
2. Flowers of terrestrial orchids also can be identified from the labellum as in the epiphytic orchids.

Note
When you see an orchid flowering in wild, please do not pluck it. Instead leave it for others to see and enjoy too. Take a picture instead. Also, be informed that in many countries it is illegal to uproot wild plants from their natural habitat. Furthermore, once a wild plant is uprooted from its native habitat, it is sure to die sooner than later.